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April 21, 2020

Genome data of Fusarium oxysporum f. sp. cubense race 1 and tropical race 4 isolates using long-read sequencing.

Fusarium wilt of banana is caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. cubense (Foc). We generated two chromosome-level assemblies of Foc race 1 and tropical race 4 strains using single-molecule real-time sequencing. The Foc1 and FocTR4 assemblies had 35 and 29 contigs with contig N50 lengths of 2.08 Mb and 4.28 Mb, respectively. These two new references genomes represent a greater than 100-fold improvement over the contig N50 statistics of the previous short read-based Foc assemblies. The two high-quality assemblies reported here will be a valuable resource for the comparative analysis of Foc races at the pathogenic levels.


April 21, 2020

Towards PacBio-based pan-eukaryote metabarcoding using full-length ITS sequences.

Development of high-throughput sequencing techniques have greatly benefited our understanding about microbial ecology; yet the methods producing short reads suffer from species-level resolution and uncertainty of identification. Here we optimize PacBio-based metabarcoding protocols covering the Internal Transcribed Spacer (ITS region) and partial Small Subunit (SSU) of the rRNA gene for species-level identification of all eukaryotes, with a specific focus on Fungi (including Glomeromycota) and Stramenopila (particularly Oomycota). Based on tests on composite soil samples and mock communities, we propose best suitable degenerate primers, ITS9munngs + ITS4ngsUni for eukaryotes and selected groups therein and discuss pros and cons of long read-based identification of eukaryotes. This article is protected by copyright. All rights reserved.


April 21, 2020

Full-length mRNA sequencing and gene expression profiling reveal broad involvement of natural antisense transcript gene pairs in pepper development and response to stresses.

Pepper is an important vegetable with great economic value and unique biological features. In the past few years, significant development has been made towards understanding the huge complex pepper genome; however, pepper functional genomics has not been well studied. To better understand the pepper gene structure and pepper gene regulation, we conducted full-length mRNA sequencing by PacBio sequencing and obtained 57862 high-quality full-length mRNA sequences derived from 18362 previously annotated and 5769 newly detected genes. New gene models were built that combined the full-length mRNA sequences and corrected approximately 500 fragmented gene models from previous annotations. Based on the full-length mRNA, we identified 4114 and 5880 pepper genes forming natural antisense transcript (NAT) genes in-cis and in-trans, respectively. Most of these genes accumulate small RNAs in their overlapping regions. By analyzing these NAT gene expression patterns in our transcriptome data, we identified many NAT pairs responsive to a variety of biological processes in pepper. Pepper formate dehydrogenase 1 (FDH1), which is required for R-gene-mediated disease resistance, may be regulated by nat-siRNAs and participate in a positive feedback loop in salicylic acid biosynthesis during resistance responses. Several cis-NAT pairs and subgroups of trans-NAT genes were responsive to pepper pericarp and placenta development, which may play roles in capsanthin and capsaicin biosynthesis. Using a comparative genomics approach, the evolutionary mechanisms of cis-NATs were investigated, and we found that an increase in intergenic sequences accounted for the loss of most cis-NATs, while transposon insertion contributed to the formation of most new cis-NATs. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.


April 21, 2020

SyRI: identification of syntenic and rearranged regions from whole-genome assemblies

We present SyRI, an efficient tool for genome-wide identification of structural rearrangements (SR) from genome graphs, which are built up from pair-wise whole-genome alignments. Instead of searching for differences, SyRI starts by finding all co-linear regions between the genomes. As all remaining regions are SRs by definition, they can be classified as inversions, translocations, or duplications based on their positions in convoluted networks of repetitive alignments. Finally, SyRI reports local variations like SNPs and indels within syntenic and rearranged regions. We show SyRItextquoterights broad applicability to multiple species and genetically validate the presence of ~100 translocations identified in Arabidopsis.


April 21, 2020

Draft Genome Assembly and Annotation of Red Raspberry Rubus Idaeus

The red raspberry, Rubus idaeus, is widely distributed in all temperate regions of Europe, Asia, and North America and is a major commercial fruit valued for its taste, high antioxidant and vitamin content. However, Rubus breeding is a long and slow process hampered by limited genomic and molecular resources. Genomic resources such as a complete genome sequencing and transcriptome will be of exceptional value to improve research and breeding of this high value crop. Using a hybrid sequence assembly approach including data from both long and short sequence reads, we present the first assembly of the Rubus idaeus genome (Joan J. variety). The de novo assembled genome consists of 2,145 scaffolds with a genome completeness of 95.3% and an N50 score of 638 KB. Leveraging a linkage map, we anchored 80.1% of the genome onto seven chromosomes. Using over 1 billion paired-end RNAseq reads, we annotated 35,566 protein coding genes with a transcriptome completeness score of 97.2%. The Rubus idaeus genome provides an important new resource for researchers and breeders.


April 21, 2020

Complete genome sequence of Bacillus velezensis JT3-1, a microbial germicide isolated from yak feces

Bacillus velezensis JT3-1 is a probiotic strain isolated from feces of the domestic yak (Bos grunniens) in the Gansu province of China. It has strong antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, Mannheimia haemolytica, Staphylococcus hominis, Clostridium perfringens, and Mycoplasma bovis. These properties have made the JT3-1 strain the focus of commercial interest. In this study, we describe the complete genome sequence of JT3-1, with a genome size of 3,929,799 bp, 3761 encoded genes and an average GC content of 46.50%. Whole genome sequencing of Bacillus velezensis JT3-1 will lay a good foundation for elucidation of the mechanisms of its antimicrobial activity, and for its future application.


April 21, 2020

Chromosome-level assembly of the common lizard (Zootoca vivipara) genome

Squamate reptiles exhibit high variation in their traits and geographical distribution and are therefore fascinating taxa for evolutionary and ecological research. However, high-quality genomic recourses are very limited for this group of species, which inhibits some research efforts. To address this gap, we assembled a high-quality genome of the common lizard Zootoca vivipara (Lacertidae) using a combination of high coverage Illumina (shotgun and mate-pair) and PacBio sequence data, with RNAseq data and genetic linkage maps. The 1.46 Gbp genome assembly has scaffold N50 of 11.52 Mbp with N50 contig size of 220.4 Kbp and only 2.96% gaps. A BUSCO analysis indicates that 97.7% of the single-copy Tetrapoda orthologs were recovered in the assembly. In total 19,829 gene models were annotated in the genome using a combination of three ab initio and homology-based methods. To improve the chromosome-level assembly, we generated a high-density linkage map from wild-caught families and developed a novel analytical pipeline to accommodate multiple paternity and unknown father genotypes. We successfully anchored and oriented almost 90% of the genome on 19 linkage groups. This annotated and oriented chromosome-level reference genome represents a valuable resource to facilitate evolutionary studies in squamate reptiles.


April 21, 2020

Genome-wide selection footprints and deleterious variations in young Asian allotetraploid rapeseed.

Brassica napus (AACC, 2n = 38) is an important oilseed crop grown worldwide. However, little is known about the population evolution of this species, the genomic difference between its major genetic groups, such as European and Asian rapeseed, and the impacts of historical large-scale introgression events on this young tetraploid. In this study, we reported the de novo assembly of the genome sequences of an Asian rapeseed (B. napus), Ningyou 7, and its four progenitors and compared these genomes with other available genomic data from diverse European and Asian cultivars. Our results showed that Asian rapeseed originally derived from European rapeseed but subsequently significantly diverged, with rapid genome differentiation after hybridization and intensive local selective breeding. The first historical introgression of B. rapa dramatically broadened the allelic pool but decreased the deleterious variations of Asian rapeseed. The second historical introgression of the double-low traits of European rapeseed (canola) has reshaped Asian rapeseed into two groups (double-low and double-high), accompanied by an increase in genetic load in the double-low group. This study demonstrates distinctive genomic footprints and deleterious SNP (single nucleotide polymorphism) variants for local adaptation by recent intra- and interspecies introgression events and provides novel insights for understanding the rapid genome evolution of a young allopolyploid crop. © 2019 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.


April 21, 2020

Morphological and genomic characterisation of the hybrid schistosome infecting humans in Europe reveals a complex admixture between Schistosoma haematobium and Schistosoma bovis parasites

Schistosomes cause schistosomiasis, the worldtextquoterights second most important parasitic disease after malaria. A peculiar feature of schistosomes is their ability to produce viable and fertile hybrids. Originally only present in the tropics, schistosomiasis is now also endemic in Europe. Based on two genetic markers the European species had been identified as a hybrid between the ruminant-infective Schistosoma bovis and the human-infective Schistosoma haematobium.Here we describe for the first time the genomic composition of the European schistosome hybrid (77% of S. haematobium and 23% of S. bovis origins), its morphometric parameters and its compatibility with the European vector snail and intermediate host Compatibility is a key parameter for the parasites life cycle progression. We also show that egg morphology (a classical diagnostic parameter) does not allow for differential diagnosis while genetic tests do so. Additionally, we performed genome assembly improvement and annotation of S. bovis, the parental species for which no satisfactory genome assembly was available.For the first time since the discovery of hybrid schistosomes, these results reveal at the whole genomic level a complex admixture of parental genomes highlighting (i) the high permeability of schistosomes to other speciestextquoteright alleles, and (ii) the importance of hybrid formation for pushing species boundaries not only conceptionally but also geographically.


April 21, 2020

Complete Genome Sequence of Hydrocarbon-Degrading Halotolerant Acinetobacter radioresistens DD78, Isolated from the Aconcagua River Mouth in Central Chile.

Acinetobacter radioresistens strain DD78 (= CCUG 69565) is a soil hydrocarbon-degrading and biosurfactant-producing bacterium isolated from chronically crude oil-polluted soil of the Aconcagua River mouth in Chile. The 3.25-Mb A. radioresistens DD78 genome (41.8% GC content) was completely sequenced, with 4 replicons, 2,970 coding sequences, and 77 tRNAs.Copyright © 2019 Macaya et al.


April 21, 2020

Complete Genome Sequence of Azoarcus sp. Strain DD4, a Gram-Negative Propanotroph That Degrades 1,4-Dioxane and 1,1-Dichloroethylene.

Azoarcus sp. strain DD4 can cometabolically degrade 1,4-dioxane and 1,1-dichloroethylene (1,1-DCE) when grown with propane and other substrates. The complete genome sequence of strain DD4 reveals a diverse collection of bacterial monooxygenase genes that may contribute to its versatility in degrading commingled groundwater pollutants.Copyright © 2019 Deng et al.


April 21, 2020

Genome Sequences and Methylation Patterns of Natrinema versiforme BOL5-4 and Natrinema pallidum BOL6-1, Two Extremely Halophilic Archaea from a Bolivian Salt Mine.

Two extremely halophilic archaea, namely, Natrinema versiforme BOL5-4 and Natrinema pallidum BOL6-1, were isolated from a Bolivian salt mine and their genomes sequenced using single-molecule real-time sequencing. The GC-rich genomes of BOL5-4 and BOL6-1 were 4.6 and 3.8 Mbp, respectively, with large chromosomes and multiple megaplasmids. Genome annotation was incorporated into HaloWeb and methylation patterns incorporated into REBASE.Copyright © 2019 DasSarma et al.


April 21, 2020

High-Quality Draft Genome Sequence of Fusarium oxysporum f. sp. cubense Strain 160527, a Causal Agent of Panama Disease.

Fusarium oxysporum f. sp. cubense is the causal agent of banana Fusarium wilt, also known as Panama disease. Here, we present a high-quality genome sequence of F. oxysporum f. sp. cubense strain 160527. The genome assembly is composed of 12 contigs with a total assembly length of 51,139,495?bp (N50 contig length, 4,884,632?bp). Copyright © 2019 Asai et al.


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